This thesis aims to explore the possible explanations of the late-time accelerated expansion of our universe observed by a wide range of astronomical probes based on Earth as well as in space. We perform this study by mainly studying the properties of a mysterious major component called Dark Energy. Chapter 1 describes an upcoming radio-astronomy interferometric telescope in South Africa called Hydrogen Intensity Real-time Analysis eXperiment (HIRAX), the objectives of which include the detection of an observational probe called Baryon Acoustic Oscillation which could help us better understand the properties of Dark Energy. Chapters 2 and 3 describe the indirect study of Dark Energy properties via weak gravitational lensing of Galaxy Number counts in a standard model of our Universe and of the Cosmic Microwave Background for an observer in a large-scale local void universe. Finally, I conclude the thesis in chapter 4 by providing a summarized discussion and a brief outlook on some future possible extensions of this work.